Method of making welt insoles



METHOD OF MAKING WELT INSOLES Filed June 21, 1941 2 Sheets-Sheet 1 May 9, 1944. w Q WRIGHT 2,348,583

METHOD OF MAKING WELT INSOLES Filed June 21, 1941 2 Sheets-Sheet 2 fimmmgy v Patented May 9, 1944 2,348,583 METHOD OF MAKING WELT INSOLES Wallace C. Wright, Sanbornville, N. H. Application June 21, 1941, Serial No. 399,049

7 2 Claims.

My present invention is a novel and improved method of making insoles for use in boots and shoes, whereby said insole is formed with a permanently flexible and yieldable sewing rib for the attachment of the upper, welt, insole and outsole.

I have discovered that an improved welt insole with a permanently flexible sewing rib can be economically and advantageously manufactured by utilizing suitably plasticized thermo-plastic resins, composed essentially of cyclized high molecular weight hydrocarbon chains, or suitably plasticized thermoplastic derivatives of cellulose, such as those produced by the esteriflcation of cellulose with one or more of the low molecular weight organicaliphatic acids.

Suchsynthetic plastic materials can now be made of suflflcient inherent strength to constitute the stitch-retaining and welt-connecting means between the insole and outsole of a welt type of boot and shoe. A novel method of preparing the material to constitute such a permanently plastic and yielding sewing rib, and incorporating the same with the insole, enables me to provide an insole structure commercially and at a relatively slight expense. By having such an improved insole with a permanently flexible sewing rib, I am enabled to produce a permanently flexible shoe, which is a result long desired in this art. Furthermore, by an inherently and initially flexible sewing rib, no ridges or gutters are formed in the insole during wear, as is the case with a rigid sewing rib.

In carrying out my invention; I first provide a sheet or strip of textile material and coat the same with a thin friction or other coating of the synthetic plastic material to be utilized for the sewing rib. Thereupon, the sheet or strip is cut into suitable widths, preferably, equal to two sewing ribs and attaching flanges to be made therefrom. Thereupon, the strip so prepared is drawn thru a suitable die and simultaneously a second coating of synthetic plastic material is applied to the already coated surface of the textile base or layer, together with a pair of suitably formed ribs adjacent each edge of the strip which are to constitute the sewing ribs in the completed insole. 'Ihereupon I separate the strip with the two ribs thus formed by a zig-zag cut intermediate the rib portions and lengthwise of the strip, thus forming two separate. sewing rib and attaching flange structures suitable to be secured by cement to the marginal edge of the insole of any size, shape, or contour, as will be explained.

Furthermore, I may, if desired, notch or pink the outer edge portion of the strip adjacent the base of the flange to facilitate the conformation of the rib strip thus prepared around sharp-toad or arch portions of the insole, while maintaining duce a rib 'and flange with any part suitable to lay flat around the toe.

By means of my novel, permanently flexible inseam, sewing rib of synthetic plastic or other flexible material, with capacity for uniting the same directly to the insole blank of any material,

- by cement or adhesive, I provide an extremely simple, rapid, and-efllcient'method of manufacture, and produce an insole with a sewing rib of great strength, sufficient to eliminate the gemming operation although it is, of course, feasible to add such reinforcing as gemming, if desired.

- Such a flexible stitch-retaining rib may be made by extruding, molding, rolling, folding, or any suitable manner to pre-form the same and prepare it for attachment to the insole.

Referring to the drawings illustrating preferred embodiments of mypresent invention:

Fig. 1 is a diagrammatic view of a sheet of textile material, having a preliminary coating of synthetic plastic material suitable for the subsequent rib and coating attachment on the coated side; while the textile layer is preferable for the flange part flat and eliminating bunches paruniting to the insole by adhesive;

Fig. 2 illustrates a strip cut from the sheet shown in Fig. 1; in both these figures the thickness of the textile layer and coating are overdrawn for clarity;

Fig. 3 is a view in perspective of a fragmentary portion of the strip after the pair of sewing ribs have been added, this being shown on an enlarged sca e;

Fig. 4 is a plan view showing the zig-zag cut separating the two ribbed portions into each individual sewing rib for attachment to an insole;

Fig. 5 is a plan view illustrating the process of cementing and attaching the prepared rib to an insole;

Fig. 6 is an enlarged fragmentary view in crosssection showing the margin of an insole with my improved sewing rib and a reinforcing strip;

Fig. 7 is a view corersponding to Fig. 6 without any reinforcing, and

Fig. 8 is a fragmentary cross-sectional view illustrating a shoe structure and also a reinforcing gemmed duck layer where same is desired.

In my developments and improvement in the boot and shoe art wherein synthetic plastic material is utilized, as illustrated in my prior and copending applications Ser. Nos. 348,387, flied July 30, 1940; and 357,293 filed September 18, 1940, I have shown and explained various improvements and developments in this art. However, it has been found extremely diflicult to utilize a suitably strong synthetic plastic which could be cemented to an insole blank of leather another suitable material. I have, therefore, in my present invention discovered that by providing a thin textile layer on which the synthetic plastic material was built up or applied, I was then enabled to secure such a flexible syntheticrib structure to an insole blank by a simple cementing operation, as the textile layer and cement would adhere properly to the insole blank n the textile surface, and the synthetic coated layer would present an affinity for the plastic rib or structure on the synthetic coated surface.

As shown in Fig. 1, therefore, I have illustrated diagrammatically a sheet of textile material I, to which a thin coating 2 of synthetic plastic, either of the same material as that from which the sewing rib is to be constructed or a sufiiciently simi- Iar synthetic material, to merge with the rib plastic when a strip cut from the sheet is drawn thru a die, which die applies the plastic material to the plastic coated surfaced. The thickness of both the textile material I and the preliminary coating 2 is greatly overdrawn inthe attached drawings, as previously noted.

With the coated sheet I as illustrated, I then cut the same along suitable lines 33 into strips such as illustrated in Fig. 2, this strip being equal in width for two subsequent rib structures to be out therefrom. With the strip thus prepared, I then draw the same thru a suitable die which applies a second coating 5 of plastic, which will merge with the coating 2 into a homogenous mass for the length and width of the strip, and also form, simultaneously, a pair of sewing ribs 6-6 adjacent each side of the edge of the strip, thus providing an outer marginal surface of the base of each rib 6, and a relatively thickened intermediate portion 8 between the ribs 6-6. Thereupon, I subject the strip thus prepared to a zig-zag cutting operation, designated as 9, in Fig. 4, thus forming two ribbed structures with homogenous bases or flanges, said flanges particularly from the inner portion 8 being of sumcient width to afford a strong union between the flanged rib strips and the insole to which the same are to be attached.

Such pinked or V-shaped flange structure is designated generally at l0 and, if desired, the outer flange I may also be pinked, as illustrated at l2. Thus the pinked flange portions of Ill and i2 of each separated strip, together with the sewing rib 6, may be quickly and expeditiously applied around the marginal edge of an insole blank l5, irrespective of the contour, while maintaining the pinked flange portions I0, and whether or not the outer flange 1 is also pinked evenly and smoothly around the insole particularly at the toe, as best shown in Fig. 5.

Furthermore, the strip or rib and flanged synthetic material as thu prepared, with the textile face I on the lower or bottom portion, has a capacity for being applied around curves at any part of its length and does not require any separate hand-pinking or the like, as is often necessary in laying a flat piece of leather at curves.

In my improved structure, it is thus prepared ready for attachment both to straight and convex soles, concave curves, and the flanged portions will be maintained flat while the perpendicularly extending rib portions will, of course, follow such a curve without difliculty. 7

Furthermore, by having this rib structure of synthetic plastic material, which is permanently flexible for the life of the shoe, the laying of same on an insole blank I5 is greatly facilitated. 7

With the insole structure thus completed and as indicated in Fig. 7, it can then be utilized in welt shoe manufacture entirely independently of gemming or reinforcing, although the latter may be employed if desired.

As shown in Fig. 6 I have illustrated a reinforcing strip 20 which can be applied, if desired; and in Fig. 8 I have illustrated a typical gemmed duck layer 2| in a completed shoe structure wherein the insole l5 with its attached plastic sewing rib is incorporated in the shoe uniting the upper materials 23 and 24 by inseam stitching 25 to a welt 26, and the latter by the outsole stitching 28 to the outsole 30, the shoe also being completed by the filling 33 and, where desired, the sewing rib B is trimmed where desired during the upper trimming, as indicated at 35.

My invention of an inherently and permanently flexible sewing rib suitable for manufacture as a distinct article in the shoe trade, and preferably pre-pinked to facilitate the application to any part of the rib around the toe of an insole is, I believe, a distinct novelty and greatly benefits the complete shoe structure and also renders the same permanently flexible. Such a flexible rib is, preferably, formed of synthetic plastic material, but I contemplate also utilizing a flexible substance or combination, such as canvas, fibreglass, rock wool, or other permanently flexible material which is stitch-retaining and, preferably, of a substance suitable to be applied to an insole blank by adhesive. Also, I may form my novel type of rib with the stitch-retaining rib portion and the lower attaching flange portion mounted on a strip of canvas or the like, with the latter of greater width than the flange portion. Thus, as shown in Figs. 5 and 7, I have shown in dotted lines at 40 where the flange portion of the rib material could end and the attaching strip extending beyond the same, which would still further facilitate the tapering effect and, hence, smoothness between the surface of the insole blank and the attaching flange, which is also increased by the pinking effect, as will be readily appreciated.

I claim:

1. The improved method of making a welt insole, having an unchanneled insole blank and an adhesively secured sewing rib of synthetic plastic material mounted upon a textile base, which consists in first applying a coating of said synthetic plastic material to a sheet of textile material, drying said coating, cutting the coated material into strips, and thereupon applying to the coated surface a mass of said synthetic plastic material, a horizontal portion extending widthwise of said coated strip and having two upstanding ribs adjacent the marginal edges of said strip, thereupon severing the said strip by a zig-zag cutting action between the upstanding rib portions to form said strip into two individual sewing rib members with a pinked flange on each, and thereupon adhesively securing the textile surface to the marginal edge of the insole, blank, by progressively apply said strip thereto.

2. The improved method of making a welt insole, having an unchanneled insole blank and an adhesively secured sewing rib of synthetic plastic material mounted upon a textile base, which consists in first applying a coating of said synthetic plastic material to the base textile material, and thereupon applying to the coated surface a mass of similar synthetic plastic material, having a horizontal portion adapted to be united'with said coating, and an upstanding rib portion integral therewith to receive inseam stitching, and thereupon adhesively securing the uncoated surface of the textile base material to the marginal edge of the insole blank.

WALLACE C. WRIGHT, 

